1. Field of the Invention
The present invention relates to a multi-stage watertight chamber. More particularly, the present invention relates to a multi-stage watertight chamber that can store leaked-in water in one watertight chamber, and prevent damage to devices installed inside another watertight chamber.
2. Descriptions of the Related Art
FIG. 1 illustrates a waterproof structure 1 being applied to a shaft of motor equipment or apparatus in deep-water. The motor 10 must be protected inside the housing 11. A shaft 12 protrudes through the housing 11 to drive a load, such as a propeller 13. It is difficult to prevent the high pressure liquid outside the waterproof structure 1 from seeping in because the shaft 12 is usually rotating at high speed. Therefore, a rotary seal 14 is disposed at a position where the shaft 12 protrudes through the housing 11 to make sure waterproof status is achieved when the shaft 12 rotates. However, pressurized liquid in deep water could still leak into the housing 11 and cause damage to the equipment or apparatus installed in the housing 11 providing any flaw present with the rotary seal 14. The shaft length is long and requires the shaft 12 to be separated into a motor shaft 121 coupled to the motor 10 and a propeller shaft 122 coupled to the propeller 13. A clutch 15 is then coupled to the motor shaft 121 and the propeller shaft 122 to ensure the smooth turning of the shaft 12.
Besides, the user can only determine whether liquid is leaking into the housing 11 by disassembling the housing 11 for inspection. In addition, internal space is required inside the housing 11 to store liquid leaked into the housing 11. Said space can also be equipped with an electrical water ingress sensing means to detect early sign of water ingress in an effort to prevent damage of motor 10 or other equipment from excessive liquid accumulation. However, without a mean to visually verify the severity of the water ingress situation and a quick way to remove the accumulated liquid inside, it then requires relatively large space in the housing 11 to store water seepage until they can be removed. In this case, a risk of damage to the equipment or apparatus in the housing 11 by liquid and its vapor can not be under estimated.